1. Field of the Invention
The present invention relates to arrowheads, used in connection with arrows, for the sport of archery or for hunting. More particularly, the present invention relates to a mechanically expandable broadhead having a single fixed, deflection-resistant spear-point blade at the tip thereof, in combination with multiple pivotally movable blades.
2. Description of the Background Art
People in the field of archery or bowhunting commonly use arrowheads for: (1) preserving the integrity of an arrow; (2) maintaining an accurate arrow flight pattern; and (3) creating a more effective means of harvesting game.
In the past, to maintain the integrity of an arrow, some type of metal has been provided at the arrow tip. Metals used for arrowhead manufacture include stainless steel and steel alloys. Titanium is also becoming fairly common in arrow tip manufacture.
While almost any metal arrowhead would suffice to preserve an arrow""s structural integrity, one objective, among arrowhead makers, is to create an arrowhead that both maintains an accurate flight pattern, and maximizes the effectiveness of a strike, to allow the bow-hunting enthusiast to efficiently harvest game. An arrowhead with relatively small blades provides accurate arrow flight, but offers a less effective or efficient means of harvesting game. In contrast, an arrowhead with large blades gives the arrow a less effective flight pattern, but provides for a more effective strike and harvest.
Today, selected hunters and some archery enthusiasts use mechanically expandable broadhead-type arrowheads. The expandable blade arrowhead offers a combination of both accurate arrow flight and effective harvest ability, in a single arrowhead. Expandable blade arrowheads tend to be accurate during flight, since the arrowhead remains small in diameter. Upon contact with the target or game, the arrowhead expands in diameter as large blades spring open, creating a larger area of penetration, and consequently, a more effective harvest. In this type of arrowhead, expansion of the blades, from a stored position to a fully deployed position, is caused by the mechanical action of the arrowhead striking the target.
Several inventors have independently patented different designs for mechanically expandable arrowheads.
U.S. Pat. No. 4,940,246 to Stagg (1990) discloses a mechanically expandable arrow attachment and/or arrow head in which two actuator members protrude from opposite sides of a cylindrical central body. When the arrowhead of Stagg strikes a target, the actuator members open integrally attached cutting blades, which are initially folded into the central body. During deployment of the cutting blades, the actuator members move through the cylindrical body and emerge on the opposite side.
While the Stagg reference discloses the combination of a fixed arrow tip with mechanically expandable blades, the actuator members of Stagg are spaced significantly away from the fixed tip, requiring significant entry depth of the fixed tip into a target before the mechanical blades begin to expand. In addition, in the design of Stagg, the actuator members are located relatively close to the pivot point, providing a relatively small lever arm to pivotally move the blade.
U.S. Pat. No. 5,178,398 to Eddy (1993) discloses another use of expandable blades. A rubber band is positioned over two expandable blades, to keep the blades closed during an arrow""s flight. The band""s position also prohibits the opening of the blades until the arrowhead penetrates its target, as the blades must break the band to expand.
U.S. Pat. No. 5,803,848 to Anderson (1998) uses a tip-actuated method of deploying two retractable blades. However, in typical hunting conditions it is possible that debris could collect in the actuator lip of the arrowhead of this design, limiting the effectiveness of the arrow.
U.S. Pat. No. 6,015,357 to Rizza (2000) contains two opposed blades that can either remain stationary or become expandable, depending on the consumer""s desired use.
Several arrowhead patents have been issued with expandable blades retained by an annular member, such as an O-ring or rubber band, during flight. U.S. Pat. No. 5,322,297 to Smith (1994), U.S. Pat. No. 5,564,713 to Mizek et al. (1996) and U.S. Pat. No. 5,879,252 to Johnson (1999) all contain expandable blades retained by an annular member; however, none of these arrowheads contain a fixed-in-place blade, to ensure that the arrowhead retains some level of effectiveness, in the event that the expandable blades fail to deploy.
It has been discovered that if the known expandable blade arrowheads do not hit directly on a solid target area, or if they strike a target at an angle, these arrows may become deflected rather than entering into the target. Expandable blade arrowheads have been known to xe2x80x9cbounce offxe2x80x9d or ricochet away from the target in some instances. In addition, expandable arrowheads of the known type may have a greater tendency to bounce off than standard arrows, because of the requirement of the target causing the blades to open mechanically.
While the known arrowheads have some utility for their intended purposes, a need remains for improvement in the arrowhead art. A need exists for an arrowhead having expandable blades, in which actuators for the expandable blades are situated close to a fixed blade at the tip of the arrowhead, in order to minimize the time between entry of the fixed blade and the beginning of deployment of the expandable blades.
The present invention provides an improved arrowhead, which features mechanically expandable blades, and which also includes a xe2x80x9ccut-on-contactxe2x80x9d spear-point blade, fixedly mounted at the tip of the arrowhead, to provide entry into the target before the expandable blades are deployed, in order to resist deflection of the arrowhead.
In the arrowhead according to a first embodiment of the present invention, expandable blade actuator spurs are situated close to a fixed blade at the tip of the arrowhead, in order to minimize the time between entry of the fixed blade and the beginning of deployment of the expandable blades.
An arrowhead, according to the first embodiment, includes a support body having a substantially conical tip portion, with a central slot formed therein to receive the fixed spear-point blade. The support body also has longitudinal slots formed in the sides thereof, which allows it to serve as a housing for two or more pivotally attached expandable blades.
At the base of the support body, a threaded shaft is provided to allow the arrowhead to be threadably and rotatably mounted in a threaded bore at the front of an arrow shaft.
The expandable blades are disposed in a semi-retracted configuration during arrow flight, with actuator spurs extending outwardly from the support body, proximate the base of the fixed blade.
The fixed spear-point blade may be a substantially diamond-shaped double-edged fixed blade, attached to the front of the support body in the central slot, between the expandable blades, to form the leading edge of the arrow tip. Alternatively, the fixed blade may be substantially teardrop-shaped. The cutting edges of the fixed blade may be flat and continuous, or may alternatively be made serrated.
Each blade is attached by a suitable fastener, which closely conforms to the exterior surface of the support body, to minimize wind resistance during flight. The fastener is preferably made removable, in order to allow the blades to be replaced, should they become damaged or worn. As noted, the arrowhead according to the first embodiment of the invention includes at least two pivotally movable and expandable blades. In an alternative embodiment, three or four expandable blades may be used.
The fastener for attaching the fixed front spear-point blade to the support body may be a screw. In a preferred embodiment, the fastener fits into a threaded bore, formed substantially transversely to the longitudinal axis of the support body. The fastener also passes through a pre-cut hole provided in the spear-point blade, to retain the blade in fixed relation to the support body.
Where two expandable blades are used, the blades may both be fastened to the support body with a single fastener. Alternatively, each of the expandable blades may be separately fastened to the support body.
Each of the fasteners, selected to interconnect one or more of the expandable blades to the support body, operates in a dual capacity. First, the fastener attaches one or more of the expandable blades to the support body. Second, it operates as the fulcrum on which the expandable blade pivots to its opened state.
During arrow flight, and when not in use, the expandable blades are retained in the closed configuration thereof by an elastic band or O-ring.
Each of the expandable blades includes a small, yet highly functional spur, which is situated at or near the leading edge of the expandable blade when it is in its closed configuration. The spurs extend outwardly beyond the support body while the blades are in the closed position. Preferably, in the closed configuration of the arrowhead, the spurs are situated at the forwardmost end of the expandable blades, adjacent the fixed blade at the tip of the support body.
The spurs"" purpose is two-fold. First, the spurs help provide stability in the arrow""s flight as they counter-balance the wind shear of the fixed blade; and second, upon the arrowhead""s contact with the target, the spur impacts against the target surface, forcing the blade rearwardly. This rearward movement of the blades either breaks the elastic retaining ring or moves it rearwardly on the arrow shaft. Once the pivotally attached blades expand, the bases of the blades anchor against the support body slot, orienting the sharp cutting edges of the blades facing forwardly, to provide the maximum effective cutting surface.
It is an object of the present invention to provide a mechanically expandable broadhead which also includes a fixed blade at the tip portion thereof.
It is a further object of the invention to provide a mechanically expandable broadhead of the type described, in which a plurality of actuator spurs are located close to the fixed blade, to provide quick opening of the expandable blades shortly after the tip enters a target.
For a more detailed presentation of the invention, the following section offers a detailed description accompanied by drawings. Throughout the following detailed description and drawings, like numbers refer to like parts.